In this press forming method, a formed product which has a hat-shaped cross section, and which is provided with a top surface portion, an outward corner portion, a vertical wall portion, an inward corner portion, and a flange portion, is formed. In a draw forming step, an intermediate formed product 8 including a protruding portion 81 and a recessed portion 83 is formed. The curvature of the protruding portion 81 and the recessed portion 83 are greater than those of the outward corner portion and the inward corner portion, and the cross-sectional shape of the protruding portion 81 is caused to bulge further toward the top surface portion side in a pressing direction F than the outward corner portion. In a restrike forming step, the outward corner portion and the inward corner portion are formed by pushing the protruding portion 81 down in the pressing direction F.

A shape change prediction method for a press formed part for predicting a shape change of the press formed part with a lapse of time units after springback at a moment of a release from a die includes: a shape/residual stress immediately after springback acquisition step of acquiring a shape and a residual stress of the press formed part immediately after the springback by a springback analysis of the press formed part; a residual stress relaxation/reduction setting step of setting a value of a residual stress relaxed and reduced from the acquired residual stress to the press formed part immediately after the springback; and a shape analysis step of determining a shape, in which moments of force are balanced, for the press formed part to which the value of the relaxed and reduced residual stress is set.

A shape change prediction method for a press formed part for predicting a shape change of the press formed part with a lapse of time units after springback at a moment of a release from a die includes: a shape/residual stress immediately after springback acquisition step of acquiring a shape and a residual stress of the press formed part immediately after the springback by a springback analysis of the press formed part; a residual stress relaxation/reduction setting step of setting a value of a residual stress relaxed and reduced from the acquired residual stress to the press formed part immediately after the springback; and a shape analysis step of determining a shape, in which moments of force are balanced, for the press formed part to which the value of the relaxed and reduced residual stress is set.

Provided is a press-formed article manufacturing method including pressing a blank with the first pressing apparatus to form a first intermediate formed article having a pair of bent portions bent to one side in the plate thickness direction and having a spacing between the bent portions narrower than the width of the top plate and equal to or more than the width of the top portion of the convex portion, and moving the second die relative to the second punch side punch with respect to the die pad and the second punch and forming a second intermediate formed article in a state where a portion between the bent portions is sandwiched between the die pad and the convex portion, with one side of the first intermediate formed article in the plate thickness direction as the convex portion side of the second pressing apparatus.

A domer station having a domer assembly, a housing assembly, and a stacked piston assembly is provided. The domer assembly is movably disposed within a domer body passage located in the housing assembly and structured to move between a forward, first position and a retracted, second position. The stacked piston assembly includes a plurality of pistons, preferably three pistons, disposed in series and a pressure supply. The pistons are disposed behind the domer in pressure chambers. The pistons have a constant pressure applied thereto and are biased towards the domer. The pistons are, however, each restrained by a stop and do not contact, or operatively engage, the domer when the domer is in the domer first position.

A domer station having a domer assembly, a housing assembly, and a stacked piston assembly is provided. The domer assembly is movably disposed within a domer body passage located in the housing assembly and structured to move between a forward, first position and a retracted, second position. The stacked piston assembly includes a plurality of pistons, preferably three pistons, disposed in series and a pressure supply. The pistons are disposed behind the domer in pressure chambers. The pistons have a constant pressure applied thereto and are biased towards the domer. The pistons are, however, each restrained by a stop and do not contact, or operatively engage, the domer when the domer is in the domer first position.

A ram assembly includes an elongated ram body and a punch mounting assembly. The ram body has a reduced length. The punch mounting assembly includes an elongated body having a complementary length. The punch mounting assembly is coupled to the ram body. The assembled punch mounting assembly and ram body have an operational length.

A ram assembly includes an elongated ram body and a punch mounting assembly. The ram body has a reduced length. The punch mounting assembly includes an elongated body having a complementary length. The punch mounting assembly is coupled to the ram body. The assembled punch mounting assembly and ram body have an operational length.

There is provided a method for manufacturing a bottomed cylindrical body, the method being capable of achieving both a conventional hard can manufacturing process such as drawing and ironing and reduction in the cost and the environmental load in a degreasing step. The method for manufacturing a bottomed cylindrical body includes a lubricant application step of applying liquid (lubricant) having a viscosity of lower than 200 mPa.Math.s to a surface of a metal plate, a drawing step of drawing the metal plate to which. the lubricant has been applied, with use of a forming member having a processing surface having a hardness of Hv 1000 to 12000, an ironing step of ironing, with use of another forming member having a processing surface having a hardness of Hv 1500 to 12000, a workpiece with a coolant interposed between the workpiece and the another forming member, to form a bottomed cylindrical body, and a degreasing step of degreasing oil on a surface of the bottomed cylindrical body with use of a cleaning agent. The concentration of oil contained in the coolant is lower than 4.0 percent by volume. The cleaning agent contains any one of sulfuric acid, hydrofluoric acid, potassium carbonate, sodium hydroxide, and potassium hydroxide. The temperature of the cleaning agent in the degreasing step is lower than 75° C.

There is provided a method for manufacturing a bottomed cylindrical body, the method being capable of achieving both a conventional hard can manufacturing process such as drawing and ironing and reduction in the cost and the environmental load in a degreasing step. The method for manufacturing a bottomed cylindrical body includes a lubricant application step of applying liquid (lubricant) having a viscosity of lower than 200 mPa.Math.s to a surface of a metal plate, a drawing step of drawing the metal plate to which. the lubricant has been applied, with use of a forming member having a processing surface having a hardness of Hv 1000 to 12000, an ironing step of ironing, with use of another forming member having a processing surface having a hardness of Hv 1500 to 12000, a workpiece with a coolant interposed between the workpiece and the another forming member, to form a bottomed cylindrical body, and a degreasing step of degreasing oil on a surface of the bottomed cylindrical body with use of a cleaning agent. The concentration of oil contained in the coolant is lower than 4.0 percent by volume. The cleaning agent contains any one of sulfuric acid, hydrofluoric acid, potassium carbonate, sodium hydroxide, and potassium hydroxide. The temperature of the cleaning agent in the degreasing step is lower than 75° C.